Question

Dielectric constant, property of an electrical insulating material (a dielectric) equal to

• A. the ratio of the capacitance of a capacitor filled with the given material to the capacitance of an identical capacitor in a vacuum without the dielectric material.
• B. the capacitance of a capacitor filled with the given material
• C. the ratio of the capacitance of a capacitor filled with the given material to the capacitance of an identical capacitor in a vacuum with the dielectric material.
• D. none of the above

Answer 1

Answer: (A)

The capacitance of a parallel plate capacitor filled with the given material of dielectric constant $K$ is given by:

$C=\frac{K{\epsilon }_{0}A}{d}$ .....................eq1

And the capacitance of the same capacitor without the given material is given by:

$C^{\prime }=\frac{{\epsilon }_{0}A}{d}$ .....................eq2

Dividing eq1 by eq2,

$C/C^{\prime }=K$